Method of improving the mechanical and dyeing properties of shaped polyvinyl alcohol structures



Unite tates NIETHOD OF HVIPROVING THE MECHANICAL AND DYEING PROPERTIES OF SHAPED POLY- VINYL ALCOHOL STRUCTURES No Drawing. Filed May 26, 1955, Ser. No. 511,432

Claims priority, application Japan, Dec. 17, 1951 19 Claims. (Cl. 8115.5)

The invention relates to a method of improving the mechanical and dyeing properties of shaped polyvinyl alcohol structures, and this application is a continuationin-part of our copending application, Serial No. 307,388, filed Aug. 30, 1952, now Patent No. 2,806,166.

It is known that polyvinyl alcohol structures, such as films and particularly fibers and the like, obtained from polyvinyl alcohol solutions have an insufficient resistance to hot water and have to be subjected to specific aftertreatmeuts to increase their water resistance and mechanical strength, for instance to a heat treatment and acetalization with aldehydes, such as formaldehyde.

The heat treatment, for instance, in the manner described in the application, Ser. No. 300,375, by Tsukumo Tomonari and Shigeki Nomura, filed July 23, 1952, decreases the solubility of the polyvinyl alcohol structures in water, but they remain still soluble in water of 90 to 100 C. Subsequent acetalization with formaldehyde improves the water resistance to a degree that the structures shrink less than percent of their original length when immersed for 5 min. in boiling water. Said treatments increase also the softening point of the structures in air to above 200 C. This high heat resistance in water decreases, on the other hand, their ability to absorb dyestuffs in about the same ratio as the acetalization increases. Fibers having a high degree of acetalization are difficult to be dyed in deep shades with direct colors and cannot be dyed satisfactorily with acid and acid mordant dyestufis. This can be explained by the decrease of the numher of accessible hydroxyl groups in a heat treated and acetalized polyvinyl alcohol fiber, which hydroxyl groups are largely responsible for the absorption or substantivity of the fiber toward dyestufis through hydrogen bonding.

It is, therefore, a principal object of our invention to provide a method for improving the dyeing properties and simultaneously the mechanical properties of shaped structures which consist of polyvinyl alcohol or of polymers containing at least 80 percent by Weight of vinyl alcohol units.

Another object of the invention is to provide a polyvinyl alcohol fiber, which combines excellent dyeing properties with high resistance to boiling water and good elastic recovery properties and which is suitable for textile purposes.

Other objects and advantages will become apparent from a consideration of the specification and claims.

According to the invention, shaped polyvinyl alcohol structures, particularly filaments or fibers, are treated with an aminoaldehyde or acetal thereof. Such aminoaldehydes contain trivalent nitrogen in form of a primary,

2 secondary, or tertiary amino group and in the broadest form may be represented by the formula wherein Am is an aliphatic, aromatic or alicyclic group containing at least one primary, secondary, or tertiary amino group; besides carbon and hydrogen, said Am group may also contain oxygen, sulphur, halogen, or nonbasic nitrogen atoms. Furthermore, it may contain a heterocyclic ring containing at least one basic nitrogen connected through the basic N to R. R is an aliphatic aromatic or alicyclic group, which, in addition to hydrocarbon may contain basic or non-basic nitrogen, oxygen, sulphur or halogen; n is 1 or 2; Useful amino-aldehydes and aminoacetals in accordance with the invention have the formula RgR NRA .where A is a member of the group consisting of -CHO, 3)2 2 5)z 3 i)z and R is a member of the group consisting of saturated hydrocarbon radicals having l-l7 carbon atoms, a phenylene-radical, a chloro-substituted phenylene radical, a nitro-substituted phenylene radical,

a -CH radical, a-on-onron radical CHO (3H0 a OO-CHr radical a CH -CH -O-CH -CH radical,

CH -CH SCH radical;

R is a member of the group consisting of hydrogen, a saturated hydrocarbon radical having 1-12 carbon atoms, a benzyl radical, a phenyl radical, an aminomethyl radical, an aminoethyl radical, a carboxymethyl radical, a hydroxyethy-l radical, a cyanoethyl radical, a mercaptoethyl radical, an acetonyl radical, an acetyl radical, and a -CI-I CHO radical;

R is a member of the group consisting of hydrogen, a saturated hydrocarbon radical having l-6 carbon atoms, a benzyl radical,

OCHz O-GH;

aGHiCH radical anda CHz--CH2-CH O-CHs and a radical R and R together form the cyclic residue of a piperidino or morpholino radical.

For example, for fl-cyclohexyl-amino-butyraldehyde dimethyl acetal,

GIL-CH2 Ris-CH-CHr, R2 is H, and RaisCHi OH- H; CHz-Ofiz for B-amino-acetaldehyde dimethyl acetal, R is 0 and both R and R are H; for N-methyl amino acetaldehyde dimethyl acetal, R is CH R is CH and 3 R is H; for p-amino-butyraldehyde dimethyl acetal, R is CH''CH and both R and R are H; and for 'N dirnethfl amino acetaldehyde dimethyl acetal, Ris CH and both R3 and R are CH In 'the following, we give an illustrative but not limitative list of the various groups of such suitable 'am'in'oaldehydes: I I I I ('1) Aldehydes or acetals having aprii'nai'y amino group are, for instance, beta-amino?ropionaldehyde,

'beta-amino-butyraldehyde,

the isomeric amino-valera'ldehyde's,

betaamino-ethoxy -acetaldehyde,

beta: (beta-amino-ethoxy) b'utyraldehfzde,

beta- (beta-amino 'ethyl thio )'-'propio'naldehyde, para-amino-phenoxy-acetaldehyde, para-amino-ortho-chlorobenzaldeliyde, 1v para-amino-meta-nitrobenzaldehyde and the acetals of the sam'e with methyl, ethyl, and other alcohols or ethyleneglycol.

(2) Aldehydes or acetals having secondary or tertiary aininogroups. H p p Such compounds may berepresented by the formula (2) ;'Am,,.R,,,.(CH) 1A wherein a and b are integers between i and 2, n is an integer from 1 to about 17, A is an aldehyde group CHO or an acetal group CH(OR) R being alkyl, and Am is an amino group, in which at least onehydrogen is substituted by an alkyl, aryl or alicyclic group, or a heterocyclic ring containing nitrogen and linked through said nitrogen to the R .(CH) A radical R is an aryl or alkyl group, which latter have side chains; R need not be present, but if present It can be 0. Compounds corresponding to Formula Zare, for instance,

I fi N dimethyl-amino -butyraldehyde,

'B-N pip'eridino-butyraldehyde, 'y-N-dimethyl-amino-butyraldehyde, 'y-N-dibutyl-amino-butyraldehyde, para-dimethyl-amino-benzaldehyde, ortho-diethyl-amino-benzaldehyde, morpholino acetaldehyde, piperidino-acetaldehyde, B-piperidino-propionaldehyde,

and others or the acetals of these compounds with methylalcohol, ethylalcohol, propylalcohol, butylalcohol, 'glycols and other alcohols.

4 '(3) Secondary and tertiary amino aldehydes having substitutions containing oxygen, sulfur, chlorine or nonbasic nitrogen, for instance,

beta-(beta-methyl-amino-ethoxy) -propionaldehyde, (beta-ethyl-amino-ethyl-thio) -a'ce'taldehyde, para-methylamino-ortho-chloro-benzaldehyde, 'para-dimethyl-amino rneta-nitrobenzaldehyde.

(4) Primary, secondary and tertiary amino dialdehydes or their semi-or tetra-acetals, for instance,

methylanrino-m-alonic dialdehydes, 2-ethylamino ghItaIic-dialdehyde, 2-amino-succindialdehyde, ortho-dimethylamino-terephthalaldehyde,

N,N-bis- ([3,,8-dimethoxyethyl) -cyclohexyl'arnino, N,N-bis-('y,'y-dimethoxypropyl)-rnethylamine, imino-diacetaldehyde and the corresponding propionand butyraldehydes.

(5) Primary, secondary and tertiary amino aldehydes having two amino groups in the molecule and having other elements such as oxygen, sulphur, non basic nitrogen or halogen in the molecule, for instance,

N-(aminomethylamino) -acetaldehyde, A N-(aminomethyl-cyclohexylarnino -acetaldehyde and the corresponding propionand butyraldehydes; N-(carboxymethylamino)-acetaldehyde, beta- (hydroxyethylaminm -acetaldehyde, beta-(beta-cyanoethylamino) -acetaldehyde, beta- (mercaptoethylamin-o -acetaldehyde, acetonyl-amino-acetaldehyde, also the corresponding derivatives of higher aldehydes, para acetylamino ortho chlo'ro benzaldehyde, para carbonymethylarnino ortho benzalclehyde, and others, as well as the aceta-ls of said amino aldehydes with methyl, ethyl, or other alcohols or glycols.

The amino-acetalization of the shaped polyvinyl alcohol structures is best carried out in the liquid phase, preferably in aqueous solution. It is accelerated by addition ofan acid,'s'uc'h as hydrochloric acid, sulphuric acid, nitric acid, phosphoric acid. Furthermore, to prevent or restrict swelling of the structures, a water soluble alcohol or a salt may be added to the amino-acetalization solution; suitable inorganic salts are sodium sulfate, potassium sulfate, ammonium sulfate, zinc sulfate, magnesium sulfate, copper sulfate, aluminium sulfate, alum, sodium- 'bisulfate, ammoniumbisulfate, sodiumchloride, potassium chloride, sodium nitrate, sodium phosphate, and others.

The reaction temperature should be at least 30 'C. and not higher than C., preferably not higher than 70 C. The time of reaction may vary between 5 minutes and '10 hours and 'is preferably about half an hour to several hours. When the reaction is carried 'out in aqueous solu'tionfthe concentration of the aminoaldehyde should be preferably about 0.2 to 10 percent by'weight of the acetalizing solution.

Though the reaction is preferably carried out in aqueous solution, it can also be effected in the vapor phase. 'In this case, the polyvinyl alcohol structures may be placed first in a solution containing an acid or an acid and a salt, and are then treated with the vapor of the respective amino-aldehyde or amino-acetal, or they are first placed in a solutionof the amiuo-alde'hydeor acetal and then treated with the vapor of a volatile'acid.

The rate and degree of amino-acetalization will depend on the composition of the amino-acetalizing solution and on the reacting conditions. The rate of'reaction is increased at high temperature, at high concentration of acid and amino'aldehyde or amino-acetal and at low concentration of additional salts. A desired amino-ac'etali- 'z'ation degree can be obtained by controlling these factors. The shape and history of the polyvinyl alcohol structures under treatment also influence the rate of reaction. The rate of amin0-acetalization decreases when 5 the wet heat resistanc'e'was increased by previous heat treatment. The more hydroxyl groups of the polyvinyl alcohol are blocked by preceding treatments, the lower is the obtainable amino-acetalization.

-6 at 220 C. for 3 minutes and the fiber mass was then divided in two portions, which were amino-acetalized as set forth in the table under the same conditions with a mono-amino and a diamino acetal.

TABLE 1 /CHzCH2 OCH, CH -CHz OCH; Amino-acetal CE; CHNHCH2-OH CE: CHNCHz-CH GET-CH1 OCH; CHz-CHz OCH:

Hr-CHrNHz Cone. of amino-acetal (percent) 2.0 2.3 Conc.oiamino-acetal (mole/100 gr of bath) 0.01 0.01 H1804 20 20 fi t-t t f 1 1 i 11'" a quan 1 yper par p0 yvmy a co Temp. C.) 70 70 N (percent) Degree of Amino-acetali- N (percent) Degree of Amino-acetalization, mol (percent) zation, n10] (percent) Furthermore, there is a difference in the rate of aminoacetalization due to the structure of the amino-aldehyde or amino-acetal employed.

The amino-acetalization according to the method of this invention improves the dyeability of polyvinyl alcohol not only for direct dyestuffs but also acid dyestufis and acid mordant dyestuffs. The dyeability can be improved with such a small quantity of basic nitrogen as 0.02% in the amino-acetalized product. Optimum nitrogen content varies according to the shape and history of polyvinyl alcohol articles, but generally it lies between 0.02% to 5% by weight of nitrogen, and the most preferable content of nitrogen lies between 0.05% and 1% by weight. Although the nitrogen content may be readily increased, this is not necessary because under ordinary dyeing conditions, dyeing solutions containing several percent of a dyestufi based on the Weight of fibers can be almost completely exhausted without introducing more than 1% of nitrogen.

If amino-aldehydes or amino-acetals having two or more basic nitrogen atoms are employed, the quantity The aflinity to acid or acid mordant dyestuff depends not only on the amount of bound nitrogen introduced by aminoacetalization but also on the basicity of the acetalizing amino-compound. The basicity decreases in the order tertiary--secondary-primary amine, but is somewhat influenced by other radicals combined with the nitrogen of the amino group. Generally, it may be said that the dyestuff affinity of the amino-acetalized fiher is the better, the greater the basicity of the aminocompound. Besides the dyeability, the wet heat resistance is improved. Tertiary amino-compounds are most effective to increase the wet heat resistance, while .secondary and primary amino-aldehydes are slightly inferior. Amino-aldehydes or amino-acetals containing two or more aldehyde radicals cause cross-linking and the wet heat resistance is generally superior and is raised further by a higher degree of arnino-acetalization.

Table 2 shows comparative tests made with polyvinyl alcohol fibers, which were heated for 3 min. at 230 C. in nitrogen, with an amino monoand the corresponding dialdehyde.

TABLE 2 CHzCHa OCH: CHrCHz /CH2CH(OCHa)2 Kind of amino-acetal HzC CH-NH-CHz-CIE CH1 CHN\ CHz-CHa OCHg CHPCH CHrCIEKOCHa): Cone. of amino-acetal (percent) 2.0 2. 7 Cone. of amino-acetal (mole/100 gr bath) 0.01 0.01 H28 04 (percent) 20 20 NEQSO; (percent) 10 10 Bath quantity per 1 part of polyvinyl alcohol 50 Temp. C.) 70

Softening Dissolving tem- Shrinkage Softening Dissolving tcm- Shrinkage point in Water perature C.) in 100 0. water point in water perature 0.) in 100 0.

( 0.) (percent) 0.) water (percent) 1 hr.0.14 7 1 hr.0.15'7 Ream N (Percent) 9n 5 h 0 6 Dissolved 92 5 h |0 7 Vfnsoluble 41 r.- 5 r 0 Do i 88 irisoluble 3S I nsoluble 12 of basic nitrogen introduced at an equal acetalization degree is doubled and therefore it is possible to obtain the same dyeing effect at a lower amino-acetalization degree or to shorten the reaction time.

This is shown by the tests given in Table 1. Here a wet spun polyvinyl alcohol fiber had been heated in air The degree of amino-acetalization necessary for promoting the dyeability is rather low so that the wet heat resistance may not be sufliciently improved. To obtain a higher wet heat resistance, it is preferable to use formaldehyde or other aldehydes in combination with the amino-aldehydes ofthe present process, and a heat treatment in air or another gas should preferably be carried out prior to acetalization. In such heat treatment, polyvinyl alcohol fibers spun by a wet or dry spinning method are dried and then heated in air, nitrogen, superheated steam or alcohol vapors at a temperature of 140350 C. for a suificient time to give a softening point in water higher than 80 C. (less than shrinkage when immersed for 5 min). The time of the heat treatment may be shortened at higher temperatures, especially at a temperature above 250 C., but then the treatment should not be longer than a few seconds.

A fiber which is perfectly resistant to boiling water can be obtained by combining amino-acetalization and the acetalization with formaldehyde or another aldehyde. In this case, polyvinyl alcohol fibers after the heat treatment are amino-acetalized and then formalized or vice versa or both processes can be carried out at the same time. Instead of formaldehyde, other lower aliphatic aldehydes such as acetaldehyde and propionaldehyde can be used. By combining the amino acetalization with acetalization of above mentioned lower aliphatic aldehyde the Wet heat resistance of the products is improved, and the dyeability remains substantially equal to that of fibers only amino-acetalized. Formalization after amino-acetalization is generally readily carried out, but amino-acetalization after formalization is more or less difficult depending on the degree of the preceding formalization. In such case an amino-aldehyde having high reactivity should be selected under conditions which accelerate the amino-acetalization. This applies also to the procedure where the amino-acetalization is carried out at the same time as the formalization. The formalization with an aliphatic aldehyde is carried out until at least 20% and preferably at least 30% of the hydroxyl groups in the polyvinyl alcohol have reacted but it should be stopped before more than about 50% of the hydroxyl groups are acetalized.

The fibers obtained according to the invention are oriented polyvinyl alcohol-polyvinyl acetal fibers. When the acetalization is only an amino-acetalization, 0.1 to 15 percent of the hydroxyl groups of the polyvinyl alcohol are acetalized by the amino-aldehyde, i.e. the ratio of (A) units to (B) units CHr-CHOHr-CH is between 01:99.9 to 15:85, whereby Am has the same significance as in Formula 1.

When this fiber is dyed in 2% of the direct dyestuff, diamine Blue 2B (Color Index No. 406) and 12.5% of Na SO in a bath ratio 1:50 for one hour at 70 C., more than 90% of the dyestuff in the bath is exhausted. In contradistinction, the same heat-treated fiber acetalized only with formaldehyde exhausts less than 30% of the same dyestutf under the same conditions. If dyed with 2% Resorcine Brown SRK, 2% H 50 and 5% Na SO with a bath ratio 1:50 for 1 hour at 60 C., more than 90% of the dyestuff is exhausted, while the corresponding formaldehyde acetalized fiber exhausts less than 30% of the dyestufi under the same conditions.

If the fibers are amino-acetalized as well as acetalized, they contain in addition to the (A) and (B) units (C) units wherein R is hydrogen or an aliphatic group containing 8 1-2 carbon atoms. The ratio of the units (A) :(B) (C) is. (0.l'15):(79.9-35):(20-50).

The softening point of this fiber is higher than 200 C. with a shrinking ratio less than 10% after immersion of 30 min. in boiling water. When this fiber is dyed by the afore-mentioned direct dye and acid dye under the aforementioned conditions at a temperature of 95 C. for the direct dye and C. for the acid dye, dye exhaustion of both is more than 90%; the dye of the direct dyestuff under the same conditions for cotton and vfscose rayon is only about 5060%, and that of the acid dyestuff for wool is 92% and for cotton and viscose rayon is about 12%.

As shown in X-ray diagrams, the fibers are composed of a portion of crystallites of polyvinyl alcohol in which few, if any, of the hydroxyl groups are acetalized, and of an amorphous portion which is a mixture of polyvinyl alcohol and polyvinyl acetal. This structure accounts for the heat resistance, hot water resistance and dyeability which are important properties obtained through the described chemical treatment of the heat-treated shaped structures.

The following examples are given to illustrate the method of the invent'on but are not to be understood as limiting the invention in any way. In the examples, unless otherwise stated, figures are given by weight, and the figures given for acetalization degree and aminoacetalization degree, respectively, designate the percentage of the original hydroxyl groups of the polyv'nyl alcohol which has been acetalized or amino-acetalized.

Example 1 Polyvinyl alcohol fiber spun by a wet or dry spinning method is heated for 5 minutes in air of 225 C., so as to raise its softening point to C., and then reacted for 3 hours at 75 C. with an aqueous solution containing 20% of sulphuric acid, 10% of sodium sulphate and 3% of dimethyl-cyclohexyl-amino-acetal. The fiber takes up 0.5% by weight of nitrogen and is not dissolved when submerged for 30 minutes in boiling water. This fiber shows a dyeing atfinity to acid dyes equivalent to wool and a better dyeing afiinity than cotton to direct dyestuffs. For instance, if it is dyed for one hour at 70 C. with a goods-liquor ratio of 1:30 in a bath containing, calculated on the weight of the fiber, 5% of the sodium salt of 5-sulpho-alpha-naphthalene-azo-alpha-naphthaleneazo-phenyl-alpha-naphthylamine-8-sulphonic acid (acid dyestuif), 2% of sulphuric acid, and 5% of sodium sulphate, a pure black shade is obtained. If it is dyed under the same conditions in a bath containing 2 percent of the sodium salt of diphenyl-disazo-bis-8-amino-l-naphtol-3, 6-disulphonic acid (direct dyestuif) and 10% of sodium sulphate, the dyestuff is almost completely absorbed and -a blue shade deeper than on cotton is obtained.

Example 2 Cyclohexyl-am no acetalized fiber as obtained according to Example 1 and having an amino-acetalization degree of 4.0% is treated for one hour at 70 C. with a solution containing 10% of sulphuric acid, 15% of sodium sulphate and 5% of formaldehyde to degree of formalization of 30.8%. Even if the obtained fiber is left for several hours in boiling water, it shrinks only 2%. When this fiber is dyed for one hour at 80 C. in the dyeing solution of Example 1, acid and direct dyestufls are almost completely absorbed and the depth of the color is hardly lowered by the formalization.

On the other hand, if the fiber is heat-treated as in Example 1, and then formalized under the same conditions as in Example 2 but without prevIous aminoacetalizatio'n and dyed with the same dyestuffs as in Example 1 and under the same dyeing conditions, it is not dyed out either by the acid or direct dyes, but only stained, and the former produces only a light brown shade, and the latter has no affinity.

in boiling water.

9 "Example '3 Apolyvinyl alcohol fiber containing 0.5 'mol percent of acet'c acid groups obtained by wet or dry spinning is cut to lengths of 10 cm.,- heated for 30 minutes in steam of kg. pressure per cm. at 160 C. to have a softening point in Water of 87 C., and then treated for 2 hours at 70 C. with an aqueous solution containing 15% of sulphuric acid, of sodium sulphate and 3% of N- benzyl-amino-acetaldehyde. The fiber takes up 0.3% of nitrogen and isnot dissolved When steeped for 10 minutes The fiber shows a dyeing atfin'ty to acid dyes similar to wool and an affinity better than cotton to direct dyes. For instance, if it is dyed in a bath containing 2% of the sodium salt of dibenzyl-diethyl-diaminoo-chloro-trfphenyl-carbinol-disulphonic acid anhydride (acid colour) under the same condition as in Example 1, the dyestuff is almost completely absorbed and a green shade clear as on wool is obtained. Kit is dyed with a 2% solution of the sodium salt of 7-sulpl1o-5-hydroxybeta naphthalene --'azo 2 methyl 5 methoxybenzene-4-azo-6-phenyl-amino-l-naphthol 3 sulphonic acid (direct dyestufi), a violet colour is obtained and the fiber shows an aflinity better than cotton.

Example 4 Benzyl-amino-acetaldehyde-acetal'zed fiber obtained as in Example 3 is treated for 1 hour at 50 C. in a solution containing 1% of hydrochloric acid, 10% of sodium chloride and 3% of formaldehyde. The fiber has then an amino-acetalization degree of 1.9% and a formalization degree of 31.2%. If it is heated for several hours in boiling water, it shrinks only 5%. If the fiber is dyed for 1 hour at 80 C. in the dye bath of Example 3, acid dyes and direct dyes show almost the same aflinity as in Example 3. v p on the other hand, if a fiber after heat-treatment as in Example 3 is formalized under the same conditions as in Example 4 but without amino-acetalization, and then dyed with the same dyes and under the same dyeing cond.'tions as in Example 3, acid dyes and direct dyes are oifly slightly absorbed.

Example 5 A fiber obtained from a vinyl alcohol-maleic anhydride copolymer prepared by saponification of a copolymer consisting of 95 mole percent of vinyl acetate and 5 mole percent of maleic anhydride is heated for 2 hours in ethyl alcohol vapor of 6.7 kg./cm. pressure at 140 C. and then treated for 1 hour at 50 C. in an aqueous solution containing of sulphuric acid, 10% of sodium sulphate, 2% of p-d'methylamino-benzaldehyde and 4% of formaldehyde. This fiber contains 0.2% of nitrogen and when steeped for 3 minutes in boiling water shows 6% shrinkage. When it is dyed with the acid color as in Example 1 under the conditions of Example 2, a pure black shade is produced.

On the other hand, when the fiber is reacted under the same conditions as above in the same bath but without the p-dfmethyl-amino-benzaldehyde, only a light brown shade is produced.

Example 6 A tube made from polyvinyl alcohol by an extrusion process is heated for 1 hour at 140 C. in an atmosphere containing air of 1.4 l g./cm. pressure and steam of 2.9 kg./cm. pressure, then treated for 2 hours at 45 C. in an aqueous solution containing 10% of sulphuric acid, of sodium sulphate and 5% of diethylaminoacetaldehyde-dimethylacetal, and finally placed for 30 minutes at 50 C. in a solution containing 2 0% of sulphuric acid, 10% of sodium sulphate and 2% of formal dehyde. If this tube is dyed for 1 hour at 60 C. with a goods-liquor ratio of 1:30 in a bath containing 3% of the sodium salt of 4-sulpho-alpha-naphthalene-azo-betanaphthol, 2% of sulphuric acid and 10% of sodium sul- '10 phate, a beautiful and clear red shade is produced. On the other hand, formalization without aminoacetalization produces under the same conditions a tube having a much lower atfinity to said dyestuff.

Example 7 Polyvinyl alcohol fibers produced by "a 'wet or dry spinning method are stretched for 2 minutes to 1.4 times of their original length injair at 210 C. and'th'en heattreated without stretching in air at 225 C. ,for 5'rninutes.

After having been steeped for 20'rninutes at 30 C. in an aqueous solution containing 20% of sulphuric 'acid and 15% of sodium sulphatefthe fibers are squeezed out to about 3 times their weight and exposed for '5 hours at 85 C. to beta-piperidino-propionaldehydevaporandsubsequently for-'2 hours at C. to formaldehyde vapor. When these fibers are dyed with the same 'dyestu'ifs and under the same conditions 'as in Example 1, directdy'e stuffs and acid dyestuffs show a far better affinit'ythan to th'e'samefiber acetalized by formaldehyde'only.

Example 8 A polyvinyl alcohol fiber which had been amino- *acetalized and formalizedas in Example 5 is placed for 40 minutes at C. in'a bath containing 1.5% of potassium dichromate and 1.5% of sulphuric acid, the goodsliquor ratio being 1:30, and is then dyed for minutes at 80 C. with a goods-liquor ratio of 1:50 in a bath containing 5% of 1,2,3-trihydroxyanthraquinone (mordant color) and 2% ofacetic acid. A deep shade is produced which is 'far better. than that w'hichiis obtained when the fiber is dyed at C. under thesam'sc'onditions, but without previous amino acetalization.

Example 9 A wet-spun polyvinyl alcohol fiber iscutto lengths of 10 cm., heated for 10 min. in air of 210 C;, and then immersed for 30 min. at 60 C. in a solution containing 15 percent by weight of H SO Q15 percent'by weight of Nat- 80 and 1 percent by weight of thedi'me'thyl acetal of beta-piperidino-propionaldehyde. Subsequently, the 'fiberis placed for 60 min. at 70C, in a solution containing 10 percent by weight of H 80 '15 percent by Eveght of Na- SO and 5 percent by weight of formalde- In this treatment, the fiber takes up 0.3 percent of nitrogen, the shrinkage when 'im'riirsed 5 r ni'r'i. in water of 100 C. is 4 percent, arid'tlie dyeability for direct and acid colors is excellent as in the previous example.

Example 10 ,A heat-treated fiber as in Example 9. is immersed 'for 60 min. at 65 C. in a bath containing 10 percent of H 80 and 1.5 percent of the dimethylacet'al of beta-phenylethylamino-propionaldehyde. Subsequently the fiber is formalized under the same condition as Example 9. The fiber takes up 0.3 percent of nitrogen and its shrinkage in water of 100 C. is 0.4 percent. i x I The fiber obtained has good afiinity to acid dyestuffs, acid 'mor'dant dyestufls, mo'rdant and direct dyestutfs.

Example 11 V A polyvinyl alcohohfiber produced by spinning an aqueous solution of polyvinyl alcohol into a saturated aqueous solution of sodium sulphate, was dried and heated for 3 minutes in hot air at 200 C., then treated in an aqueous solution containing 15% by weight of sulphuric acid, 15 by weight of sodium sulphate, 1.2% by weight of beta amino-propionaldehyde-dimethyl-acetal at 60" C. for 15 minutes.

Thefibers thus treated contained 0.64% by weight of nitrogen and showed very good dye'abili-ty with acid dyestufi. If, for instance, the fibers were dyed with; 2% by weight (based on the weight of fiber) or, Aci d Brilliant Scarlet; 3.R (Colorlndex No. the fibers absorbed the dyestuff completely.

11 Example 12 The fibers prepared by the same manner as in Example 11 were treated in an aqueous solution containing 10% by Weight of H SO 15% by weight of Na SO and 5% by weight of formaldehyde at 70 C. for one hour.

The thus treated fibers were not softened at all, even if the fibers were continuously boiled in water for one hour and the shrinkage was negligible.

The above treatment did not affect the dyeability with acid dyestuffs, and the dyeability was similar to that of Example 11.

Example 13 Polyvinyl alcohol fibers cut to lengths of cm. were heat-treated in air at 210 C. for 10 minutes and then treated in an aqueous solution containing 10% by weight of H 30 by weight of Na SO and 0.5% by weight of beta-amino-butyraldehyde-diethylacetal at 60 C. for 30 minutes.

Said fibers were further treated in an aqueous solution containing 10% by weight of H 80 15% by weight of Na SO and 5% by weight of formaldehyde at 70 C. for one hour. The fibers after treatment were not softened if boiled in water continuously for one hour and showed excellent dyeability with acid dyestuffs. If the fibers were dyed with 2% by weight of Tartrazine (Color Index No. 640), they absorbed completely the dyestuif from the bath.

Example 14 The same polyvinyl alcohol fibers as in Example 11 were treated in an aqueous solution containing 10% by weight of H 80 15 by weight of Na SO and 0.5% by weight of beta-amino-butyraldehyde-dimethylacetal at 70 C. for 30 minutes. The treated fibers contained 0.45% of nitrogen and had excellent dyeability with acid dyestuffs and direct dyestuffs.

The fibers were then treated further in an aqueous solution containing 10% by weight of H 80 15 by weight of Na SO and 5% by weight of formaldehyde at 70 C. for one hour; the resulting fiber had a shrinkage of less than 5% if boiled in water for one hour and the dyeability was excellent, similar to that before formalization.

Example 15 The polyvinyl alcohol fiber according to Example 11 was treated in an aqueous solution containing by weight of H 80 15% by weight of Na SO 2% by weight of formaldehyde and 2% by weight of beta-aminobutyraldehyde-dimethylacetal at 70 C. for minutes. The nitrogen content of the treated fibers was 0.25% and the shrinkage in boiling water after one hour was less than 3% and the fiber showed excellent dyeability with acid or direct dyestuffs.

Example 16 A polyvinyl alcohol fiber produced by spinning an aqueous solution of polyvinyl alcohol through a saturated aqueous solution of sodium sulphate was dried and stretched to a drawing ratio 1.4/1 in air at 200 C., heated for 5 minutes maintaining the original length in steam of 2 kg./crn. pressure at 220 C. and then immersed for 20 minutes at 60 C. in an aqueous solution containing 20% by weight of H 50 15% by weight of Na SO and 1% by weight of beta-amino-butyraldehyde-diethylacetal. This fiber contained 0.6% by Weight of nitrogen and had a superior dyeability to direct dyes, mordant dyes and acid mordant dyes at a temperature between 50 C. and 70 C. For example, when this fiber was immersed in a dyeing bath containing 2% of weight (based on the weight of fiber) of Diamine Blue 28 (Color Index No. 406) for one hour at 60 C., it absorbed almost completely the employed dyestuif from the dyeing bath. The dyeability of the fiber for this dyestulf is superior to that of cotton and viscose rayon.

12 Example 17 Polyvinyl alcohol fibers produced by extruding an aqueous solution of polyvinyl alcohol into a saturated aqueous solution of sodium sulphate were dried, cut to lengths of 10 cm., heated for one hour in steam of 5 kg./cm. pressure at a temperature of 160 0, immersed for 10 minutes at room temperature in an aqueous solution containing 20% by weight of H and 10% by weight of Na SO squeezed to 250% of the original weight of fiber, dried by atmospheric drying to of the weight of the fiber, reacted with the vapor of beta-aminopropionaldehyde-dimethylacetal for 30 minutes at 80 C. and then reacted with formaldehyde for one hour at 70 C. in the vapor of an aqueous solution containing 30% by weight of formaldehyde employing an enclosed vessel.

The fibers were resistant to boiling water and had superior dyeability.

Example 18 The amino-acetalized fiber obtained according to Example 3 was treated for 1 hour at 50 C. in an aqueous solution containing 10% of sulphuric acid, 5% of sodium sulphate and 5% of acetaldehyde. This fiber had an acetalization degree of 28.5% and an amino acetalization degree of 2.0%; when steeped for 1 hour in boiling water, it showed 8% shrinkage. If the fiber was dyed for 1 hour at 80 C. in the same solution as in Example 3, it showed the same atfinity as in Example 3 to acid and direct dyestuffs.

On the other hand, when the fiber was heat-treated as in Example 3, acetalized with acetaldehyde under the same conditions as in Example 18 without amino acetalization, and then dyed with the dyestuffs and under the dyeing conditions as in Example 3, the acid dyestuff yielded a very light green shade, and the direct dyestufi a light violet shade.

Example 19 A polyvinyl alcohol fiber heat-treated as in Example 9 is immersed for 30 minutes at 60 C. in a solution containing 15% of sulphuric acid, 1.5% of p-benzylamino-butyraldehyde-dimethylacetal, 40% of methyl alcohol and 43.5% of Water and then immersed for 60 minutes at 70 C. in a solution containing 10% of sulphuric acid, 15% of sodium sulphate and 3% of acetaldehyde.

This fiber contains 0.3% nitrogen and shows good afilnity to acid and direct dyestuffs, and has also good resistance to boiling water.

Example 20 Polyvinyl alcohol bristles produced by dry spinning a concentrated aqueous solution of polyvinyl alcohol are stretched to a draw ratio of 5:1 in air of C. One part is treated for 3 hours at 60 C. in an aqueous solu tion containing 10% of H 80 25% of Na SO and 2% of cyclohexylarnino diacetaldehyde -tetrametl1ylacetal, and the other part is treated under the same conditions in an aqueous bath containing 15% of H 80 25% of Na SO and 1% of formaldehyde. Both portions are separately dyed for 1 hour at 50 C. in an aqueous bath containing Tartrazine (Color Index No. 640) 2% (based on the weight of goods). The former is dyed in a heavy yellow shade and absorbs completely the dyestuff in the bath, whereas the latter is only stained in a very light yellow shade.

Example 21 The bristle formalized as in Example 20 is further immersed for 3 hours at 70 C. in an aqueous solution containing 15% of H 80 25% of Na SO and 2% of N,N-bis-(6,;3-dirnethoxyethyl)-cyclohexylarnine and then dyed as in Example 20. A deep yellow shade is ob- 13 tained, like that produced in the first bristle portion of Example 20.

Example 22 A polyvinyl alcohol fiber is produced by spinning an aqueous solution of polyvinyl alcohol into a saturated aqueous solution of sodium sulphate containing 0.3% of sulphuric acid, dried and heat-treated for 3 min. at 225 C. in an atmosphere of nitrogen keeping the original length and immersed for 2 hours at 70 C. in an aque- Example 23 The amino-acetalized fiber obtained in Example 22 is further immersed in an aqueous solution containing of H 80 of Na SO and 5% of formaldehyde. This fiber is resistant to boiling water and the shrinkage on treatment for several hours in boiling water is only 4%. The afiinity of this fiber is as excellent as -'that of the amino-acetalized fiber of Example 22 and there is no decrease in dye exhaustion due to formalisation after amino-acetalization.

Example 24 The wet spun polyvinyl alcohol fiber obtained in Example 22 is cut to lengths of 10 cm. and treated for 1 hour at 160 C. in steam having a vapor pressure of 5 kg./cm. The obtained crimped fiber is dipped for 1 hour at 60 C. in an aqueous solution containing 7% of hydrochloric acid, 10% of sodium chloride and 1.6% of N,N-bis ('y,' -dimethoxypropyl -benzylamine. fiber has a nitrogen content of 0.2%, resistance to hot water of 95 C. and excellent dye-aflinity. For example, this fiber can completely exhaust within 1 hour at 80 C. the dyestuif in a dyeing bath containing Congov red 2%.

Example 25 A polyvinyl alcohol filament yarn (120 denier, 40 filaments) wet spun by a conventional method is heattreated for 2 seconds in air of 250 C. The yarn has a "softening point in water of 86 C. It is treated for 1 hour at 70 C. in an aqueous solution containing 15% of H 80 15% of Na SO 3.5% of N-aminomethylaminopropionaldehyde-diethylacetal and 4% of formaldehyde. formalization degree of mole percent. It is resistant to boiling water and shows good dye affinity for direct and acid colors. For example, its dye affinity is as good as that of wool in dyeing with Eriochrome Azurol B (Color Index No. 720).

Example 26 A crimped fiber heat-treated as. in Example 24 is treated for 1 hour at 70 C. in an aqueous solution containing 15% H 50 and 1%. of beta-(beta-ethylamino-ethyl)- thio-propionaldehyde and then treated 'for '30-mini1tes at 60 C. in an aqueous solution containing 10% of H 80 15% of Na SO and 2% of acetaldehyde. It

has resistance to boiling water and excellent dyeability.

Example 27 The crimped heat-treated fiber of Example 24 is immersed for 1 hour at 70 C. in an aqueous solution containing 15% of H 50 20% of methyl alcohol and3% This I It has a nitrogen content of 0.4% and a Example 28 A polyvinyl alcohol fiber obtained by wet-spinning and drying as described in Example 22 is stretched in air of 200 C. to of original length, treated for 5 minutes at 220 'C. in steam having a vapor pressure of 2 kg./cm. and then immersed for 20 minutes at 60 C. in an aqueous solution containing 20% of H SO 15% of Na SO and 1% of ,B-ethylamino-butyraldehydediethylacetal. The obtained fiber has a nitrogen content of 0.5% and shows excellent dye-exhaustion for direct, acid, mordant and acid mordant dyestuffs at 50 to 70 C. For example, when it is dyed for 1 hour at 60 C. in a dyeing bath containing Diamine Blue 28 (Color Index No. 406) 2%, it absorbs the dye completely and shows a deeper shade than cotton or viscose rayon dyed under identical conditions.

Example 29 The amino-acetalized fiber as obtained in Example 28 is further treated for 1 hour at 70 C. in an aqueous solution containing 10% of H 50 15 of Na SO and 5% of formaldehyde. It shrinks only 3% of its original length when immersed for 1 hour in boiling water, has

a softening point in air of 215 C. and excellent dyeability as in Example 21.

Example30 A crimped fiber, heat-treated as in Example 24, is steeped for 10 minutes at room temperature in an aqueous solution containing 20% of H 50 and 10% of Na SO squeezed to moisture content, further dried in air to 50% weight increase, treated for 30 minutes at 80 C. in the vapor of beta-methylamino-propionaldehydedimethylacetal, and then suspended for 1 hour in a closed vessel in which 30% formalin is vaporized at 70 C. This fiber is resistant to boiling water and shows good dyeability.

Example 31 A crimped fiber obtained by heat-treating as in Example 24 is treated for 1 hour at 70 C. in an aqueous solution containing 15 of H 80 10% of Na SO and 2% of (beta-methylamino-ethylthio)-acetaldehyde-dimethylacetal. This fiber shows good dyeability.

Example 32 The heat-treated fiber as obtained according to Example 1, is treated for 30 minutes at 70 C. with an aqueous solution containing 15% of sulfuric acid, 15%

of sodium sulfate and 0.5 of B-cyclohexylamino-butyraldehyde-dimethylacetal and then treated for 1 hour at 70 C. with an aqueous solution containing 10% of sulfuric acid, 15% of sodium sulfate and 3% of formaldehyde. This fiber has 0.46% of nitrogen and degree of formalization of 32%, and shrinks only 1.5% in boiling water for 30 minutes. When this fiber is dyed with the same dyestuffs and under the same conditions as Example 3 but at 80 C., the dyestuffs are almost completely exhausted.

Example 33 The heat-treated fiber as obtained according to Example 1, is treated for 1 hour at 70 C. with an aqueous solution containing 12% of sulfuric acid, 15 of sodium sulfate, 4% of formaldehyde and 3% of ,B-cyclohexylamino-propionaldehyde-dimethylacetal. This fiber has 0.32% of nitrogen and degree of formalization of 28%, and shrinks only 2.8% in boiling water for 30 minutes. The dyeability of this fiber is almost the same as Example 32.

Throughout the specification and claims, the term polyvinyl alcohol is used to designate also copolymers of polyvinyl alcohol with other polymerizable compounds, provided that said copolymers contain at least '80 percent by weight of polyvinyl alcohol. The terms aldehyde and amino-aldehydes, when broadly used, cover also the acetals thereof; instead of the lower aliphatic aldehydes, compounds yielding said aldehydes or decomposable thereto by acids, such as their polymers and amination products, may be used. Examples are para'formaldehyde, polyoxyethylene, hexamethylenetetramine, paraldehyde, and the like.

Though the invention is described particularly for the treatment of fibers, it may also be applied to other shaped articles, such as tubes, envelopes, films and bristles.

We claim:

1. A method of preparing solid polyvinyl alcohol films and fibers of improved dyeability which shrink less than percent of their length when immersed for 5 minutes in 90 C. water which comprises reacting solid heat treated, oriented polyvinyl alcohol films and fibers which shrink less than 5 percent of their length when immersed for 5 minutes in 80 C. water with a compound having the formula A is a member of the group consisting of -CHO, 3)2 2 5)2, 3 I)2, and 4 Q)2;

R is a member of the group consisting of saturated hydrocarbon radicals having 1-17 carbon atoms, a phenylene radical, a chloro-substituted phenylene radical, a

intro-substituted phenylene radical,

a ('3 1 1-- radical, a C "I l' CHl radical o no 0110 a :n cm-om radical, a one-@- radical a -Qo-clhradical a CH CH O-CH CH radical, and a radical;

a CHzCH-OOH3 radical )CHa a -CHzOHz-OH-O-CH3 radical O-CHs the cyclic residue of a morpholino radical jointly with R and the cyclic residue of a piperidino radical jointly with R at a temperature in the range of about 30 to 95 C. in the presence of an acid selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid for a time sufiicient to incorporate about 0.02 to 5 percent by weight of said N in the resulting product,

's'aic'l percent'being' based on the 'v'veighttif said resulting product.

2. The method according to claim 1 wherein the said solid polyvinyl alcohol films and fibers are reacted with fi-cyclohexyl-amino-butyraldehyde dimethyl acetal in the presence of sulfuric acid.

3. The method according to claim 1 wherein the said solid polyvinyl alcohol films and fibers are reacted with ff-amino propio'naldehyde dimethyl acetal in the presence of sulfuric acid.

4. The method according to claim 1 wherein -the said solid polyvinyl alcohol films and fibers are reacted with N-methyl amino acetaldehyde dimethyl acetal inthe presence of sulfuric acid.

5. The method according to claim 1 wherein the said solid polyvinyl alcohol films and fibers are reacted with ,B-amino butyraldehyde dimethyl acetal in the presence of sulfuric acid.

6. The method according-to claim 1 wherein the said solid polyvinyl alcohol films and fibers are reacted with N-dimethyl amino acetaldehyde dimethyl acetal in the presence of sulfuric acid.

7. The method according to claim 1 wherein the said solid polyvinyl alcohol films and fibers are also reacted with an aliphatic aldehyde having 1-3 carbon atoms for a time sufiicient to acetalyze about 20 to 50 percentof the hydr'oxyl groups of the polyvinyl alcohol.

8. The method of claim 1 wherein the polyvinyl alcohol films andfibers are first amino-acetalizedand then acetalized.

9. The method of claim 1 wherein the polyvinyl alcohol films and fibers are first acetalized and then aminoacetalized.

10. The method of claim 1 wherein the polyvinyl alcohol films and fibers are simultaneously acetalized and amino-acetalized.

11. A solid, oriented, self-supporting shaped polyvinyl alcohol structure of improved dyeability which shrinks less than 5 percent of its length when immersed for 5 minutes in C. water, said structure consisting essentially of:

0.1 to 15 percent amino-acetalized vinyl alcohol units having the formula I VRzRs where R is a member of the group consisting of saturated hydrocarbon radicals having 1-17 carbon atoms, a phenylene radical, a chloro-substituted phenylene radical, a nitro-substituted phenylene radical,

a CH radical, a (|3HCH2 radical CHO CH 0 R is a member of the group consisting of hydrogen, a saturated hydrocarbon radical having l12 carbon atoms, a benzyl radical, a phenyl radical, an aminoethyl radical, aminoethyl radical, a carboxymethyl radical, a hydroxyethyl radical, acyanoethyl radical, a

mercaptoethyl radical, an acetonyl radical, an acetyl radical, a CH CHO radical. the cyclic residue of a morpholino radical jointly with R and the cyclic residue of a piperidino radical jointly with R R is a member of the group consisting of hydrogen, a saturated hydrocarbon radical having 1-6 carbon atoms, a benzyl radical,

O-CHs a CHzCHzCH-OCH3 radical CHs the cyclic residue of a morpholino radical jointly with R and the cyclic residue of a piperidino radical jointly with R 79.9 to 35 percent of vinyl alcohol units,

CHz-?HCHz-CH and 20 to 50 per cent of acetalized vinyl alcohol units having the formula CH2-CH-CHzCH- (I)H t where R is a member of the group consisting of hydrogen and aliphatic hydrocarbon radicals having 1-2 carbon atoms,

said structure containing about 0.02 to 5 percent by weight of said structure of said N from the amino-acetalized vinyl alcohol units, said structure being heat treated and showing in the X-ray diagram a portion comprised essentially of polyvinyl alcohol crystallites, and an amorphous portion which is a mixture of vinyl alcohol units, said acetalized vinyl alcohol units, and said amino-acetalized vinyl alcohol units. I

12. A solid, oriented, self-supporting shaped polyvinyl alcohol structure of improved dyeability which shrinks less than 5 percent of its length when immersed for 5, minutes in 90 C. water, said structure consisting essentially of:

0.1 to 15 percent amino-acetalized vinyl alcohol units having the formula CHz-( FHCH2CH- 0-( 3H i NRzRa where R is a member of the group consisting of saturated hydrocarbon radicals having 1-17 carbon atoms, a phenylene radical, a chloro-substituted phenylene radical, a nitro-substituted phenylene radical,

a CH- radical, a CHCH2 radical CH0 CEO a OO-CHr radical a radical, -CH -CH S-CH radical;

R is a member of the group consisting of hydrogen, a saturated hydrocarbon radical having 1-12 carbon and a atoms, a benzyl radical, a phenyl radical, an aminoethyl radical, an aminoethyl radical, a carboxymethyl radical, a hydroxyethyl radical, a cyanoethyl radical, a mercaptoethyl radical, an acetonyl radical, an acetyl radical, a -CH -CHO radical, the cyclic residue of a morpholino radical jointly with R and the cyclic residue of a piperidino radical jointly with R R is a member of the group consisting of hydrogen, a saturated hydrocarbon radical having 1-6 carbon atoms, a benzyl radical,

a -cm-cnic 11-0-0 Ila radical CHs the cyclic residue of a morpholino radical jointly with R and the cyclic residue of a piperidino radical jointly with R 99.9 to percent o'f-vinyl alcohol units,

said structure containing about 0.02 to 5 percentb Weight of said structure of said N from the aminoacetalized vinyl alcohol units, said structure being heat treated and showing in the X-ray diagram a portion comprised essentially of polyvinyl alcohol crystallites, and an amorphous portion which is a mixture of vinyl alcohol units and said amino-acetalized vinyl alcohol units.

13. An oriented polyvinyl alcohol fiber of improved dyeability which shrinks less than 5 percent of its length when immersed for 5 minutes in C. water, said fiber consisting essentially of:

0.1 to 15 percent amino-acetalized vinyl alcohol units having the formula R is a member of the group consisting of saturated hydrocarbon radicals having 1-17 carbon atoms, a phenylene radical, a chloro-substituted phenylene radical, a nitrosubstituted phenylene radical,

a C H radical, a -?HCHZ radical CH0 CH0 a -ZH-crr,-omradical, a DECO radical a Oo-omradical a CH- -CH OCH -CH radical, and

a CH CH -SCH radical;

R is a member of the group consisting of hydrogen, a saturated hydrocarbon radical having 1-12 carbon atoms, a benzyl radical, a phenyl radical, an aminomethyl radical, an aminoethyl radical, a carboxymethyl radical, a hydroxyethyl radical, a cyanoethyl radical, a mercaptoethyl radical, an acetonyl radical, an acetyl radical, a -CH CHO radical, the cyclic residue of a morpholino radical jointly with R and the cyclic residue of a piperidino radical jointly with R R is a member of the group consisting of hydrogen, a

19 saturated hydrocarbon radical having 1-6 carbon "atoms, a benzyl radical,

a OH=CHOC Haradical CHs the cyclic residue of a morpholino radical jointly with R and the cyclic residue of a piper-idino radical jointly with R 79.9 to 35 percent of vinyl alcohol units,

H OH

and 20 to 50 percent of the acetalized vinyl alcohol units having the .formula where R is a member of the group consisting of hydrogen and aliphatic hydrocarbon radicals having 1-2 carbon atoms,

said fiber containing about "0.02 to 5 percent by weight of said fiber of said N from the amino-acetalized vinyl alcohol units, said fiber being heat treated and showing in the X-ray diagram a portion comprised essentially of polyvinyl alcohol crystallites, and an amorphous portion which is a mixture of vinyl alcohol units, said acetalized vinyl alcohol units, and said amino-acetalized vinyl alcohol units.

14. An oriented polyvinyl alcohol fiber of improved dyeability which shrinks less than 5 percent of its length when immersed for 5 minutes in 90 C. water, said fiber consisting essentially of:

0.1 to percent amino-acetalized vinyl alcohol units having the formula R is a member of the group consisting of saturated hydrocarbon radicals having 1-17 carbon atoms, a phenylene radical, a chloro-substituted phenylene radical, a nitrosubstituted phenylene radical,

a CH radical, a CHCH2 radical CHO H0 is EHCH2C Hz radical, is. .O H C-G radical is Oo-omradical 20 the cyclic residue of a morpholino radical jointly with R and the cyclic residue of a piperidino radical jointly with R 99.9 to 85 percent of vinyl alcohol units,

CH2-CHCH2-(]JH on OH said fiber containing about 0.02 to 5 percent by weight of said fiber of said N from the amino-acet-alized vinyl alcohol units, said fiber being heat treated and showing in the X-ray diagram a portion comprised essentially of polyvinyl alcohol crystallites, and an amorphous portion which is a mixture of vinyl alcohol units and said aminoacetalized vinyl alcohol units. 15. A fiber according to claim 13 wherein OHz-CHa R is CHCH2, R2 is H, Ra is CH2 /CH, and R1 is H H CHz-CH:

'16. A fiber according to claim 13 wherein R is -CH -CH and each of R R and R is H.

17. A fiber according to claim 13 wherein R is --CH R is CH and each of R and R is H.

18. A fiber according to claim 13 wherein a is-CH-OHzand each of R R and R is H.

19. A fiber according to claim 13 wherein R is ----CH;, each of R and R is CH;,-, and R is H.

References Cited in the file of this patent UNITED STATES PATENTS 2,310,943 Doroughet al Feb. 16 1943 2,327,872 Dahle Aug. 24, 1943 2,380,033 'Dorough et al July 10, 1945 2,403,464 Smith July 9, 1946 2,447,140 Shelton Aug. 17, 1948 2,636,803 Cline Apr. 28, 1953 2,636,804 McClellan Apr. 28, 1953 2,639,970 Tomonari May 26, 1953 FOREIGN PATENTS 509,012 Great Britain July 6, 1939 UNITED STATES PATENT cF IcE CER'HFICATMN 0F CORRECTION Patent No. 2,960,384 November 15, 1960 Tetsuro Osugi et ale It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 22, for Patent No.

2,'8O6 l66 read abandoned column 2, line 65 for "CH(lIH read -CH=CH CH CH column 3, line 31, after "are" insert each columns 5 and 6, TABLE I, first column thereof fourth item after 2 "H 30 insert (percent) =3 column 15, line 70, for "R read R column 16, line 75 for ethyl" read methyl column 18, lines 1 and 2 for "aminoethyl" read aminomethyl Signed and sealed this 18th day of July 1961a (SEAL) Attest:

' ERNEST w, SWIDER DAVID L LADD Attesting Officer Commissioner of Patents 

1. A METHOD OF PREPARING SOLID POLYVINYL ALCOHOL FILMS AND FIBERS OF IMPROVED DYEABILITY WHICH SHRINK LESS THAN 5 PERCENT OF THEIR LENGTH WHEN IMMERSED FOR 5 MINUTED IN 90*C. WATER WHICH COMPRISES REACTING SOLID HEAT TREATED,ORIENTED POLYVINYL ALCOHOL FILMS AND FIBERS WHICH SHRINK LESS THAN 5 PERCENT OF THEIR LENGTH WHEN IMMERSED FOR 5 MINUTES IN 80*C. WATER WITH A COMPOUND HAVING THE FORMULA
 11. A SOLID, ORIENTED, SELF-SUPPORTING SHAPED POLYVINYL ALCOHOL STRUCTURE OF IMPROVED DYEABILITY WHICH SHRINKS LESS, THAN 5 PERCENT OF ITS LENGTH WHEN IMMERSED FOR 5 MINUTES IN 90*C. WATER, SAID STRUCTURE CONSISTING ESSENTIALLY OF: 0.1 TO 15 PERCENT AMINO-ACETALIZED VINYL ALCOHOL UNITS HAVING THE FORMULA 